Halogenated aryl ester damping fluids and lubricants

ABSTRACT

The invention provides a method for lubricating inertial instruments such as gyroscopes and accelerometers which require flotation fluids for operation. An exemplary process comprises introducing a fluid which contains a halogenated aryl ring, to an inertial instrument, having an axis bearing and/or a slip ring, whereby the axis bearing and/or slip ring are lubricated and the internal sensing elements are floated by the dense fluid.

This application is a divisional application of Ser. No. 07/508,277,filed Apr. 11, 1990, now U.S. Pat. No. 5,177,252 which is a continuationin part of application Ser. No. 07/358401, filed May 26, 1989, nowabandoned which is a continuation of application Ser. No. 07/045897,filed May 1, 1987 now U.S. Pat. No. 4,835,304.

FIELD OF THE INVENTION

This invention relates to fluids for providing flotation and damping infloated inertial instruments, and more particularly, to a method forlubricating floated inertial instruments.

BACKGROUND OF THE INVENTION

Floated inertial instruments such as certain types of accelerometers andgyroscopes require flotation fluids for operation. Such fluids must havehigh densities to provide adequate flotation for structural components,and also require relatively high viscosities for good dampingproperties.

Presently used flotation fluids such as chlorotrifluoroethylene (CTFE),bromotrifluoroethylene (BTFE), and triazines having halogenated sidechains derived from CTFE and BTFE suffer from certain disadvantages.CTFE and BTFE cannot be obtained pure, and therefore cause instrumentanomalies such as gravity sensitive trends and hot storage sensitivity.Also, high molecular weight CTFE is a wax at room temperature. Thetriazines are of higher purity than CTFE or BTFE, but because ofdifficulties in purification they are not single component fluids, butcontain isomers such as diastereomers and head-to-head monomer units.They are also expensive, and exhibit maximum densities in the range ofonly about 2.4 grams per ml.

It would be desirable to have available high density high viscosityfluids which can be readily synthesized at reasonable cost and readilypurified.

SUMMARY OF THE INVENTION

The present invention overcomes many of the deficiencies of prior artflotation fluids by providing a diverse family of flotation fluidshaving a wide range of densities and a very wide range of viscosities,and providing these materials relatively inexpensively and in highpurity. The materials of the present invention are easier to synthesizethan many of the presently employed flotation fluids, and are relativelyinexpensive to manufacture since they are made from inexpensive startingmaterials and in many instances do not require extensive purificationoperations. Because the starting materials can be obtained pure, thefinal products can also be manufactured in very high purity and thus donot suffer from the stratification which is known to occur with formerflotation fluids upon standing.

Some of the materials of the invention have exceptionally highdensities, in the range of 2.7 g/cc and higher, thus permitting a widechoice of structural materials for the construction of the instrumentsin which they are to be used. For example aluminum and aluminumcomposites can be used in place of beryllium with flotation fluidshaving sufficiently high densities and still remain floated. This isadvantageous since beryllium is toxic, expensive, and not readilyweldable. The higher densities of the fluids of the invention also allowhigher angular momentum for the inertial instrument to be achieved for agiven size unit, or the same angular momentum to be achieved for asmaller sized float. In addition, the fluids of the invention areessentially non-flammable, and hence may be used wherever afire-resistant fluid is required. They also possess good lubricatingproperties.

The damping/flotation fluids of the invention are materials containing ahighly halogenated aryl group connected to a highly halogenated alkylgroup by an ester linkage. They are easily synthesized from readilyavailable starting materials regardless of the orientation of thelinking ester functionality. Many halogenated phenols and halogenatedbenzoic acids required for preparation of the claimed esters arecommercially available at reasonable cost. The heavily halogenated alkylcarboxylic acids which are also needed are readily prepared in highpurity and at relatively low cost by telomerization reactions andaddition of alkyl halides across the double bond in halogenatedethylenes. These materials are easily purified, and the use of highlevels of fluorine produces final esters having wide liquid ranges,while the use of high levels of bromine and iodine in the aryl part ofthe molecule produces esters of high density. Both the aryl and thealkyl portions of the final esters can be varied readily in the startingmaterials to achieve a wide range of densities and viscosities in theresulting esters.

The high density damping fluids of the invention have the generalformula ##STR1## in which X represents any of the halogens fluorine,chlorine, bromine, and iodine in any combination. The sum of the atomicmasses of the halogen atoms on the phenyl ring is at least 90. Thesubscript n is 1-5, indicating that the aryl group contains from 1 to 5halogen substituents. Y represents an alkyl group --R, an ether group--OR, an ester group --CO₂ R, an aldehyde of 1-4 carbon atoms, a ketoneof 1-4 carbon atoms, an acetal of 3-7 carbon atoms, a ketal of 4-7carbon atoms, a cyano group CN, or a nitro group --NO₂, where R is astraight, branched, or cyclic alkyl or haloalkyl group containing 1-4carbon atoms. Each o( these hydrocarbon-based groups may contain from 0to t halogen substituents selected from the group consisting of F, Cl,and Br, where t for each of the hydrocarbon-based groups is the totalnumber of hydrogen atoms contained in the corresponding unsubstitutedgroup. The aryl group may contain up to 2 such Y substituents, asindicated by the value of the subscript m being 0-2.

By "haloalkyl" is meant an alkyl group in which at least one andpreferably more than one of the hydrogen atoms have been replaced byhalogens.

Z represents an ester functionality, present in either of twoorientations, ##STR2## relative to the aryl and alkyl portions of themolecule, as shown in formula I.

R' is a straight, branched, or cyclic haloalkyl group containing 2-8carbon atoms. The halogen atoms of the R' group are selected from thegroup consisting of F, Cl, and Br. R' contains at least one F atom, andfurther contains halogen atoms in place of greater than 60% of thehydrogen atoms of the corresponding unhalogenated alkyl group. The R'group contains from 0 to a maximum of 2 consecutive CF₂ moieties, andthe sum of the atomic masses of the halogen atoms on R' is greater than135. The compound as a whole contains at least two types of halogenatoms. Finally, the sum of the number of F and H atoms in the compounddivided by the number of halogen atoms other than F in the compound is amaximum of 7. There may be from 1 to 3 Z--R' groupings on the benzenering of formula 1, as indicated by the subscript p being 1-3.

The inventive concept also encompasses mixtures of the compounds of theinvention with each other and with other materials having damping and/orlubricating properties. It further encompasses any instrument or otherapparatus which includes a fluid of the invention. Examples of suchapparatus are a gyroscope, an integrating pendulous accelerometer, and apendulous integrating gyroscopic accelerometer. Such instruments includea housing, a float, and a fluid comprising a compound according to theinvention, with the float being in contact with the fluid.

Further, as the compounds of the invention are lubricants as well asdamping fluids, the scope of the invention includes a method forlubricating two items which are in moving contact with each other, byapplying to the area of contact between them a fluid lubricantcomprising a compound according to the invention. It also includes amethod for damping relative motion between two elements of an apparatus,by disposing a fluid comprising a compound of the invention between theelements to damp motion of one relative to the other.

DESCRIPTION OF THE DRAWING

The invention will be better understood from a consideration of thefollowing detailed description taken in conjunction with the drawing, inwhich:

FIG. 1 is a generalized illustration of a gyroscope or integratingpendulous accelerometer, in which the fluids of the invention are used;and

FIG. 2 is a generalized illustration of a pendulous integratinggyroscopic accelerometer, in which the fluids of the invention are used.

DETAILED DESCRIPTION OF THE INVENTION AND DESCRIPTION OF THE PREFERREDEMBODIMENTS

In formula I, X is preferably bromine, iodine, or a mixture of these twohalogens, to provide high density in the resulting product ester, andthe benzene ring is preferably provided with 2-5 halogen substituents.

The group Y is preferably a small alkyl group such as methyl or ethyl,and may be partially or totally halogenated An example of the lattersort of substituent is the trifluoromethyl group. Preferably the benzenering of formula I contains no more than 1 such Y substituent.

The damping fluids of formula I are preferably aryl esters in which thegroup Z is ##STR3## and p=1 because such materials are somewhat easierto prepare than the alkyl esters in which Z is ##STR4## and p is greaterthan 1.

The group R' in formula I preferably contains 2-5 carbon atoms, mostpreferably, 3-4 carbons, and a maximum of 2 hydrogen atoms, thoughlonger carbon chains and higher numbers of hydrogen atoms will functionin the invention. Group R' is thus seen to be a highly halogenatedgroup, preferably a perhaloalkyl group. Fluorine, chlorine, and brominemay be employed in any combination in group R', fluorine and brominebeing preferred. Iodine is generally disfavored for use in group Rbecause it tends to hydrolyze in the presence of water, metal, and/oracidic conditions, leading to a corrosive damping fluid. Group R'preferably contains at least two types of halogen atoms. High levels offluorine are advantageous in group R' because they produce productshaving wide liquid ranges. The carbon atom of group R' located 8 to theester group preferably carries at least two halogen substituents or atleast one halogen and a further haloalkyl moiety, and is preferably nota --CH₂ -- group. Of course, the combinations of X on R' should bestable for the particular application in question.

A subclass of high density damping fluids encompassed within formula Iare materials shown generally by formula II ##STR5## in which X, Y, m,R', and p are the same as defined with respect to formula I above, but nis now 2-5 and Z is now defined as ##STR6## so that formula II definesan aryl ester. The other preferences expressed above with respect to thecompounds of formula I continue to apply to those of formula II.

A high density damping fluid encompassed by formula II is that shown informula III ##STR7## in which X is a halogen selected from the groupconsisting of fluorine, chlorine, bromine, and iodine, and n=2-5. Again,the sum of the atomic masses of the halogen atoms on the phenyl ring isat least 90. In this material Y is a substituent selected from the groupconsisting of --R and --OR, in which R is an alkyl or haloalkyl groupcontaining 1-2 carbon atoms. The subscript m=0-2, and p=1-2. Group X' isBr or Cl. Again, the sum of the number of F and H atoms in the compounddivided by the number of halogen atoms other than F is a maximum of 7.In the material of formula III, X is preferably selected from the groupconsisting of bromine and iodine, n is preferably 3-4, the group Y ispreferably methyl or ethyl, and m is preferably 1.

In Table I are shown structural formulae of several representativecompounds of the invention which have been prepared, as well as theirdensities, viscosities, and freezing points, where these are known.

                                      TABLE I                                     __________________________________________________________________________    Representative Compounds Prepared and Their Properties                                                  Density                                                                            Viscosity                                                                (g/cc)                                                                             (cp) Freezing                                                            at 135° F.                                                                  at 135° F.                                                                  Point, °C.                         __________________________________________________________________________       ##STR8##               2.36   66 <RT                                          ##STR9##               2.53   341                                                                              <RT                                          ##STR10##              2.70   978                                                                              50                                           ##STR11##              2.84 7,555                                                                              57                                           ##STR12##              2.63 2,012                                                                              <RT                                          ##STR13##              2.53 3,981                                                                              <RT                                          ##STR14##              1.93   23 <RT                                          ##STR15##              2.40 4,184                                                                              <RT                                          ##STR16##              --   --   --                                        __________________________________________________________________________

For the materials numbered 1-4 in Table I, density is a linear functionof molecular weight. It is thus apparent that increasing the bromine andiodine content of these molecules increases their densityproportionately. Also, it will be observed that the log of the viscosityof compounds 1-4 is linearly proportional to the molecular weight ofthese damping fluids. Thus, knowing the molecular weights, densities,and viscosities of several of the damping fluids in a series permitsaccurate estimation of the density and viscosity to be achieved insimilar materials having different halogen substitutions. Thispredictability of properties is confirmed by the observation that thelogs of the viscosities of compounds 3, 5, and 6 of Table I are linearlyrelated to the number of carbons attached to the aryl ring, and by thefurther observation that the viscosity of 4.5 cp predicted for Cl₃ C₆ H₂--O--CO--CF₂ --CFBr--CF₂ Br based on the data for compounds 1-4 of TableI, and the viscosity measured for compound 7 of Table I, when plotted onthe log scale of semi-log paper versus the number of carbons attached tothe aryl ring give a line which is parallel to that obtained by thesimilar plot of viscosity data for compounds 3, 5, and 6.

The damping fluids of the invention are readily synthesized by wellknown chemical reactions as shown in the equations below. ##STR17##

Equation 1 shows the reaction of a substituted phenol 50 with an acidchloride 52 to yield a substituted aryl ester 54. The acid chloride isproduced by the reaction of the corresponding carboxylic acid 56 withthionyl chloride. Equation 2 shows the reaction of a substituted acidchloride 58 (derived from the corresponding substituted benzoic acid 60)with an alcohol 62 to yield an alkyl ester 64. Alcohol 62 is derivedfrom the reduction of carboxylic acid 56 with borane, or by othersuitable reduction reactions as known to those skilled in the art.

Numerous substituted phenols 50 are known in the chemical literature. Arepresentative listing of some of these, compiled from Beilstein, isshown in Table II, which also includes the appropriate Beilsteinreferences. Similarly, many substituted benzoic acids 60 are known inthe chemical literature, and a representative listing of some of theseis presented in Table III, which is also compiled from Beilstein. Thematerials shown in Tables II and III, as well as the many other similarmaterials of the respective classes known to the art, are appropriatefor use as the precursors of the aryl portion of the product esters inthe synthesis of the fluids of the invention.

                  TABLE II                                                        ______________________________________                                        Representative Halogen-Substituted Phenols                                    ______________________________________                                        Substituted Phenol  Beilstein Reference                                       dichloro-difluoro   5      IV     663                                         2-bromo-6-chloro-4-iodo                                                                           6      I      111   d                                     4-bromo-2-chloro-6-iodo                                                                           6      II     201   f                                     2-bromo-4-chloro-3-iodo-6-nitro                                                                   6      III    853   a                                     2-bromo-4,6-dichloro                                                                              6             201   j                                                         6      II     187   i                                                         6      III    751   d                                     3-bromo-2,6-dichloro                                                                              6      III    751   h                                     4-bromo-2,5-dichloro                                                                              6      III    752   a                                     4-bromo-2,6-dichloro                                                                              6             202   a                                                         6      I      106   b                                                                II     187   k                                                                III    752   b                                     2-bromo-4,6-difluoro                                                                              6      IV     1058                                        2-bromo-4,6-diiodo  6      III    788   e                                     4-bromo-2,6-diiodo  6      II     202   n                                                                III    788   h                                     3-bromo-2,4,5,6-tetrachloro                                                                       6      I      106   e                                                                II     188   e                                     2-bromo-3,4,6-trichloro                                                                           6      III    752   d                                     3-bromo-2,4,5-trichloro                                                                           6      III    752   f                                     3-bromo-2,4,6-trichloro                                                                           6             202   b                                                                I      106   c                                                                II     188   b                                                                III    752   j                                     4-bromo-2,3,6-trichloro                                                                           6      III    752   i                                     6-bromo-2,3,4-trichloro                                                                           6      III    752   e                                     3-bromo-2,4,6-trichloro-5-nitro                                                                   6      II     234   e                                     2-chloro-4,6-diiodo 6      I      111   o                                                                II     202   b                                                                III    787   d                                     4-chloro-2,6-diiodo 6      I      112   d                                                                II     202   j                                                                III    787   i                                     2-fluoro-4,6-diiodo 6      IV     1084                                        4-fluoro-2,6-diiodo 6      III    786   l                                     3-fluoro-2,4-diiodo-6-nitro                                                                       6      III    853   g                                     2,4-dibromo-3-chloro                                                                              6      II     189   i                                     2,4-dibromo-6-chloro                                                                              6             203   e                                                                II     189   k                                                                III    758   b                                     2,6-dibromo-4-chloro                                                                              6      I      107   c                                                                II     190   a                                                                III    758   f                                     3,4-dibromo-5-chloro                                                                              6      II     190   e                                     3,5-dibromo-2-chloro                                                                              6      II     190   g                                     3,5-dibromo-4-chloro                                                                              6      II     190   i                                     3,4-dibromo-5-chloro-2,6-diiodo                                                                   6      II     203   c                                     3,5-dibromo-2-chloro-4,6-diiodo                                                                   6      II     203   a                                     3,5-dibromo-4-chloro-2,6-diiodo                                                                   6      II     203   d                                     3,4-dibromo-3-chloro-6-iodo                                                                       6      III    785   i                                     2,6-dibromo-3-chloro-4-iodo                                                                       6      III    786   a                                     4,6-dibromo-3-chloro-2-iodo                                                                       6      III    785   h                                     3,5-dibromo-4-chloro-2-iodo-6-methyl                                                              6      II     337   g                                     2,3-dibromo-4,6-dichloro                                                                          6      II     191   f                                     2,4-dibromo-3,6-dichloro                                                                          6      III    758   i                                     2,6-dibromo-3,4-dichloro                                                                          6      III    759   d                                     3,4-dibromo-2,6-dichloro                                                                          6      II     190   k                                                                III    759   e                                     3,5-dibromo-2,4-dichloro                                                                          6      II     191   b                                     3,5-dibromo-2,6-dichloro                                                                          6      II     191   d                                     3,6-dibromo-2,4-dichloro                                                                          6      II     191   f                                     4,6-dibromo-2,3-dichloro                                                                          6      III    759   b                                     3,5-dibromo-2,4-dichloro-6-iodo                                                                   6      II     201   d                                     3,5-dibromo-2,6-dichloro-4-iodo                                                                   6      II     201   n                                     3,5-dibromo-2,4-diiodo-6-methyl                                                                   6      II     338   b                                     2,4-dibromo-5-fluoro                                                                              6      III    757   b                                     2,4-dibromo-6-fluoro                                                                              6      III    757   c                                     2,6-dibromo-4-fluoro                                                                              6      III    757   d                                     2,4-dibromo-3-fluoro-6-nitro                                                                      6      III    849   f                                     2,6-dibromo-3-fluoro-4-nitro                                                                      6      III    849   g                                     4,6-dibromo-3-fluoro-2-nitro                                                                      6      III    849   e                                     2,4-dibromo-6-iodo  6      II     201   i                                     2,6-dibromo-4-iodo  6      I      111   f                                                                III    785   e                                     2,4-dibromo-3-iodo-6-nitro                                                                        6      III    853   b                                     2,6-dibromo-3-iodo-4-nitro                                                                        6      III    853   c                                     2,5-dibromo-3,4,6-trichloro                                                                       6      III    759   f                                     2,6-dibromo-3,4,5-trichloro                                                                       6      II     191   h                                     3,4-dibromo-2,5,6-trichloro                                                                       6      II     191   i                                                                III    759   g                                     3,5-dibromo-2,4,6-trichloro                                                                       6      II     191   j                                     3,5-dibromo-2,4,6-triiodo                                                                         6      II     205   d                                     3,6-dichloro-2,4-diiodo                                                                           6      IV     1085                                        2,4-dichloro-3-fluoro                                                                             6      IV     958                                         2,4-dichloro-5-fluoro                                                                             6      IV     959                                         2,4-dichloro-6-fluoro                                                                             6      IV     959                                         2,5-dichloro-4-fluoro                                                                             6      IV     959                                         2,6-dichloro-4-fluoro                                                                             6      III    715   k                                                                IV     959                                         3,5-dichloro-4-fluoro                                                                             6      IV     960                                         4,5-dichloro-2-fluoro                                                                             6      IV     960                                         2,4-dichloro-5-iodo 6      III    782   b                                     2,4-dichloro-6-iodo 6      II     200   l                                                                III    781   k                                     2,6-dichloro-4-iodo 6      I      110   c                                     pentabromo          6             206   e                                                                I      10    j                                                                II     197   d                                                                III    766   i                                                                IV     1069                                        pentachloro         6             144   b                                                                I      104   f                                                                II     182   h                                                                III    731   b                                                                IV     1025                                        pentafluoro         6      IV     782                                         2,3,4,5-tetrabromo-6-chloro                                                                       6      II     196   j                                     2,3,4,6-tetrabromo-5-chloro                                                                       6      II     197   a                                                                III    766   h                                     2,3,5,6-tetrabromo-4-chloro                                                                       6      II     197   b                                     2,3,4,6-tetrabromo-5-methoxy                                                                      6      II     821   f                                     2,3,4,6-tetrabromo-5-fluoro                                                                       7      III    535   c                                     2,3,4,6-tetrabromo-5-iodo                                                                         6      II     202   b                                     2,3,4,6-tetrabromo-5-nitro                                                                        6             248   k                                                                II     236   j                                     2,3,4,5-tetrabromo-6-methyl                                                                       6             362   f                                                                I      177   f                                                                II     337   n                                                                III    1272  e                                     2,3,4,5-tetrachloro 6      II     182   b                                                                III    729   e                                                                IV     1020                                        2,3,4,6-tetrachloro 6             193   d                                                                II     182   d                                                                III    729   f                                                                IV     1021                                        2,3,5,6-tetrachloro 6      II     182   f                                                                III    730   i                                                                IV     1025                                        2,3,4,6-tetrachloro-5-iodo                                                                        6      I      110   l                                                                III    783   k                                     2,3,5,6-tetrachloro-4-iodo                                                                        6      I      110   n                                     2,3,4,5-tetrachloro-6-methoxy                                                                     6      III    4253  c                                                                IV     5620                                        2,3,4,5-tetrachloro-6-methyl                                                                      6      I      175   e                                     2,3,4,6-tetrachloro-5-nitro                                                                       6      II     232   b                                     2,3,4,5-tetraiodo   6      IV     1088                                        2,3,4,6-tetraiodo   6      IV     1089                                        2,3,4-tribromo      6      II     192   a                                     2,3,5-tribromo      6             203   g                                                                II     192   c                                                                III    759   k                                     2,4,5-tribromo      6      II     192   e                                                                       760   c                                     2,4,6-tribromo      6             203   i                                                                I      107   e                                                                II     192   g                                                                III    760   f                                                                IV     1067                                        3,4,5-tribromo      6      II     195   a                                     2,3,4-tribromo-6-chloro                                                                           6      II     195   i                                     2,3,6-tribromo-4-chloro                                                                           6      II     195   c                                     2,4,6-tribromo-3-chloro                                                                           6      II     195   g                                     3,4,6-tribromo-2-chloro                                                                           6      II     195   c                                     2,4,6-tribromo-3-chloro-5-iodo                                                                    6      II     202   a                                     2,4,6-tribromo-3-chloro-5-methoxy                                                                 6      II     821   d                                     2,3,5-tribromo-4-chloro-6-methyl                                                                  6      II     336   g                                                                III    1272  b                                     2,3,6-tribromo-4-chloro-5-nitro                                                                   6      II     236   h                                     2,3,5-tribromo-4,6-dichloro                                                                       6      II     195   j                                     2,4,5-tribromo-3,6-dichloro                                                                       6      III    765   h                                     2,4,6-tribromo-3,5-dichloro                                                                       6             206   a                                                                II     196   a                                     3,4,5-tribromo-2,6-dichloro                                                                       6      II     196   c                                     2,3,5-tribromo-4,6-diiodo                                                                         6      II     203   f                                     2,4,6-tribromo-3,5-diiodo                                                                         6      II     203   j                                     3,4,5-tribromo-2,6-diiodo                                                                         6      II     203   h                                     2,4,6-tribromo-3-fluoro                                                                           6      III    765   a                                     2,4,6-tribromo-3-iodo                                                                             6      III    786   c                                     3,4,6-tribromo-2-iodo                                                                             6      III    786   b                                     2,4,6-tribromo-3-iodo-5-methoxy                                                                   6      II     821   k                                     2,4,6-tribromo-3-iodo-5-nitro                                                                     6      II     238   k                                     3,4,5-tribromo-2-iodo-6-methyl                                                                    6      II     337   i                                     2,3,4-tribromo-6-methoxy                                                                          6             786   a                                                                I      390   j                                                                III    4260  c                                     2,3,5-tribromo-4-methyl                                                                           6      II     386   a                                     2,3,4-tribromo-4-nitro                                                                            6      III    851   a                                     2,3,4-trichloro     6      II     179   h                                                                III    716   b                                     2,3,5-trichloro     6      II     180   a                                                                III    716   f                                     2,3,6-trichloro     6             190   f                                                                II     180   c                                                                III    716   h                                                                IV     962                                         2,4,5-trichloro     6      II     180   c                                                                III    717   d                                                                IV     962                                         2,4,6-trichloro     6             190   i                                                                I      103   l                                                                II     181   a                                                                III    722   b                                                                IV     1005                                        3,4,5-trichloro     6      II     181   e                                                                III    729   a                                     2,4,6-trichloro-3-fluoro                                                                          6      III    729   c                                     2,3,5-trichloro-4-iodo                                                                            6             209   h                                     2,3,6-trichloro-4-iodo                                                                            6             209   h                                                                I      110   i                                     2,4,6-trichloro-3-iodo                                                                            6      I      110   g                                                                III    783   i                                     2,3,4-trichloro-5-methoxy                                                                         6      IV     568   c                                     2,3,4-trichloro -6-methyl                                                                         6      I      204   d                                     2,3,5-trichloro-4-nitro                                                                           6             242   c                                     2,3,5-triiodo       6             211   k                                                                IV     1085                                        2,4,6-triiodo       6             211   n                                                                I      112   f                                                                II     203   k                                                                III    788   i                                                                IV     1085                                        3,4,5-triiodo       6      IV     1088                                        2,4,6-triiodo-3-methoxy                                                                           6      III    4343  c                                                                IV     5689                                        2,4,6-triiodo-3-methyl                                                                            6             385   a                                                                I      191   j                                                                III    1325  b                                                                IV     2075                                        2,4,6-triiodo-3-nitro                                                                             6      II     239   d                                                                III    853   i                                     Substituted Benzene                                                           1,2-dihydroxy-4-iodo                                                          1,3-dihydroxy-5-iodo                                                                              6      II     821                                         1,4-dihydroxy-2-iodo                                                                              56            667                                         2,4-dihydroxy-1-iodo                                                                              6      II     821                                         1,2-dihydroxy-3,4,5,6-tetrabromo                                                                  6      II     788                                         1,2-dihydroxy-3,4,5,6-tetrachloro                                                                 6      II     787                                         1,3-dihydroxy-2,4,5,6-tetrachloro                                                                 6      II     819                                         1,4-dihydroxy-2,3,5,6-tetrachloro                                                                 6      II     846                                         1,4-dihydroxy-2,3,4,6-tetraiodo                                                                   6      I      417                                         1,3-dihydroxy-2,4,6-tribromo                                                                      6             822                                         1,4-dihydroxy-2,3,5-tribromo                                                                      6      II     848                                         1,2-dihydroxy-3,4,5-trichloro                                                                     6      I      389                                         2,4-dihydroxy-1,3,5-trichloro                                                                     6             82                                          1,2,3-trichloro-4,5,6-trihydroxy                                                                  6             1084                                        1,2,4-trichloro-3,5,6-trihydroxy                                                                  6      II     1072                                        1,3,5-trichloro-2,4,6-trihydroxy                                                                  6      II     1144                                                            Reference                                                 1,4-dihydroxy-2-iodo                                                                              J.A.C.S. 56, 667                                          ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        Representative Halogen-Substitiuted Benzoic Acids                             Substituted Benzoic Acid                                                                         Beilstein Reference                                        ______________________________________                                        2-bromo-3-chloro   9              355   f                                     2-bromo-4-chloro   9              355   i                                     2-bromo-5-chloro   9              355   l                                                                III    1426  o                                                                IV     1027                                        2-bromo-6-chloro   9              356   a                                     3-bromo-2-chloro   9              356   f                                                                III    1426  g                                     3-bromo-4-chloro   9              356   i                                                                II     236   j                                                                III    1427  a                                     2-bromo-3-chloro-5-iodo                                                                          9       IV     1043                                        2-bromo-5-chloro-3-iodo                                                                          9       IV     1043                                        3-bromo-2-chloro-5-iodo                                                                          9       IV     1043                                        3-bromo-5-chloro-2-iodo                                                                          9       IV     1043                                        5-bromo-2-chloro-3-iodo                                                                          9       IV     1043                                        5-bromo-3-chloro-2-iodo                                                                          9       IV     1043                                        4-bromo-2-chloro-3-methoxy                                                                       10      III    260   a                                     5-bromo-2-chloro-4-methyl                                                                        9              499   j                                     2-bromo-3,5-dichloro                                                                             9       III    1427  d                                     3-bromo-2,5-dichloro                                                                             9       IV     1027                                        3-bromo-4,5-dichloro                                                                             9       III    1427  c                                     4-bromo-2,5-dichloro                                                                             9              357   g                                     4-bromo-3,5-dichloro                                                                             9       III    1428  a                                     5-bromo-2,3-dichloro                                                                             9       IV     1027                                        5-bromo-2,4-dichloro                                                                             9       III    1427  f                                     4-bromo-3,5-dichloro-2-nitro                                                                     9       III    1771  d                                     2-bromo-3,5-diiodo 9       IV     1044                                        3-bromo-2,5-diiodo 9       IV     1044                                        5-bromo-2,3-diiodo 9       IV     1044                                        3-bromo-5-fluoro   9       III    1426  c                                     3-bromo-4-fluoro   9       III    1562  d                                     2-bromo-3,4,5,6-tetrachloro                                                                      9       IV     1027                                        4-bromo-2,3,5,6-tetrachloro                                                                      9              357   i                                     4-bromo-2,3,5 (or 2,3,6)-trichloro                                                               9              357   h                                     2-chloro-3,5-diiodo                                                                              9       III    1455  f                                     3-chloro-2,5-diiodo                                                                              9       IV     1044                                        4-chloro-3,5-diiodo                                                                              9       III    1455  g                                     5-chloro-2,3-diiodo                                                                              9       IV     1044                                        2-chloro-4-fluoro  9       III    1374  d                                     3-chloro-2,4,6-triiodo                                                                           9              368   a                                     2-chloro-3,4,5,6-tetrafluor                                                                      9       IV     998                                         2,3-dibromo        9              357   j                                                                I      146   k                                                                IV     1027                                        2,4-dibromo        9              358   b                                                                I      146   l                                                                II     237   a                                                                IV     1027                                        2,5-dibromo        9              358   h                                                                I      147   a                                                                II     237   d                                                                III    1428  b                                                                IV     1027                                        2,6-dibromo        9              358   l                                                                I      147   b                                                                II     237   e                                                                III    1428  f                                                                IV     1028                                        3,4-dibromo        9              359   f                                                                I      147   c                                                                II     237   o                                                                III    1428  g                                                                IV     1028                                        3,5-dibromo        9              359   k                                                                I      147   f                                                                II     237   p                                                                III    1429  c                                                                IV     1028                                        2,3-dibromo-5-chloro                                                                             9       IV     1029                                        2,4-dibromo-6-chloro                                                                             9              360   f                                                                III    1429  f                                     2,5-dibromo-3-chloro                                                                             9       IV     1029                                        3,5-dibromo-2-chloro                                                                             9       III    1429  g                                     3,5-dibromo-4-chloro                                                                             9       II     238   b                                     3,5-dibromo-4-fluoro                                                                             9       IV     1029                                        2,3-dibromo-5-iodo 9       IV     1044                                        2,5-dibromo-3-iodo 9       IV     1043                                        3,5-dibromo-2-iodo 9       III    1453  c                                                                IV     1043                                        2,3-dichloro-5-iodo                                                                              9       IV     1042                                        2,5-dichloro-3-iodo                                                                              9       IV     1042                                        3,5-dichloro-2-iodo                                                                              9       IV     1042                                        3,6-dichloro-2-iodo                                                                              9       III    1452  f                                     2,3-diiodo         9       IV     1044                                        2,4-diiodo         9              367   k                                                                IV     1044                                        2,5-diiodo         9       I      149   i                                                                IV     1044                                        3,4-diiodo         9              3671                                                                   I      149   k                                                                II     241   m                                     3,5-diiodo         9              367   m                                                                I      149   l                                                                III    1454  g                                     3-fluoro-2-iodo    9       III    1451  f                                     4-fluoro-3-iodo    9       IV     1041                                        2,3,4,5-tetrabromo 9       II     239   a                                     2,3,4,6-tetrabromo 9              362   f                                                                I      148   b                                     2,3,4,5-tetrachloro                                                                              9              346   h                                                                III    1381  c                                                                IV     1010                                        2,3,4,6-tetrachloro                                                                              9       IV     1011                                        2,3,4,5-tetrachloro-6-iodo                                                                       9       IV     1043                                        2,3,4-tribromo     9       I      147   g                                     2,3,5-tribromo     9              360   g                                                                I      147   h                                     2,4,5-tribromo     9              360   h                                                                I      147   j                                                                III    1430  a                                     2,4,6-tribromo     9              360   i                                                                I      147   k                                                                II     238   c                                                                III    1430  b                                                                IV     1029                                        3,4,5-tribromo     9              361   f                                                                I      148   a                                                                III    1431  a                                     2,3,4-trichloro    9              345   b                                                                IV     1009                                        2,3,5-trichloro    9              345   c                                                                II     229   n                                                                III    1380  b                                                                IV     1009                                        2,3,6-trichloro    9              345   h                                                                III    1380  c                                                                IV     1009                                        2,4,5-trichloro    9              345   i                                                                I      141   k                                                                III    1380  d                                                                IV     1010                                        2,4,6-trichloro    9              345   m                                                                III    1381  a                                                                IV     1010                                        3,4,5-trichloro    9              346   d                                                                II     230   a                                                                IV     1010                                        2,3,5-triiodo      9       I      150   a                                                                III    1456  a                                                                IV     1044                                        2,4,5-triiodo      9       I      150   b                                     2,4,6-triiodo      9       III    1456  f                                     2-4,6-triiodo              IV     1045                                        3,4,5-triiodo      9              367   n                                                                III    1457  b                                     2,3,4-triiodo-6-nitro                                                                            9       II     278   k                                     ______________________________________                                    

The fluids of the invention may be mono, di, or triesters as indicatedin formula I, and in the case of di- and triesters, they may contain theester linkage Z in both orientations simultaneously within the samecompound. Equation 3 shows the reaction of a substituted hydroxybenzoicacid 66 with alcohol 62 to yield intermediate phenolic ester 68, andsubsequent reaction of this material with acid chloride 52 to yield thefinal product 70, which possesses both aryl and alkyl ester moieties.##STR18## In equation 3 it is not necessary that R' be the same in eachstep of the overall sequence.

Many hydroxybenzoic acids are known in the chemical literature, and arepresentative listing of some of these materials, compiled fromBeilstein, is presented in Table IV below. Such materials are useful asprecursors of the aryl portion of the halogenated mixed esters 70 in thesynthesis of these materials.

                  TABLE IV                                                        ______________________________________                                        Representative Halogenated Hydroxybenzoic Acids                               Substituted Benzoic Acid                                                                          Beilstein Reference                                       ______________________________________                                        3-bromo-5-chloro-2,4-dihydroxy                                                                    10     III    1379  d                                     5-bromo-3-chloro-2,4-dihydroxy                                                                    10     III    1379  f                                     3 or -4-bromo-2-chloro-5-hydroxy                                                                  10            145   b                                     4-bromo-2-chloro-3-hydroxy                                                                        10     III    259   e                                     6-bromo-2-chloro-3-hydroxy                                                                        10            145   d                                     4-bromo-2,3,5-trichloro-6-hydroxy                                                                 10     III    180   e                                     3-bromo-5-chloro-2,4-dihydroxy                                                                    10     III    1379  d                                     5-bromo-3-chloro-2,4-dihydroxy                                                                    10     III    1379  f                                     3 or -4-bromo-2-chloro-5-hydroxy                                                                  10            145   b                                     4-bromo-2-chloro-3-hydroxy                                                                        10     III    259   p                                     6-bromo-2-chloro-3-hydroxy                                                                        10            145   d                                     5-chloro-2-hydroxy-5-iodo                                                                         10            113   c                                                                II     65    i                                     2,4 or -2,6-dibromo-3,5-dihydroxy                                                                 10     III    1450  y                                     3,5-dibromo-2,4-dihydroxy                                                                         10            382   f                                                                I      179   e                                                                II     255   e                                     3,5-dibromo-2,6-dihydroxy                                                                         10     I      186   e                                     4,5-dibromo-2,3-dihydroxy                                                                         10     I      175   e                                     2,4-dibromo-5-hydroxy                                                                             10            145   f                                     2,4-dibromo-6-hydroxy                                                                             10            112   u                                                                I      49    h                                     3,5-dibromo-2-hydroxy                                                                             10            109   i                                                                I      49    d                                                                II     64    c                                                                III    181   q                                                                IV     222                                         3,5-dibromo-4-hydroxy                                                                             10            179   b                                                                I      79    b                                                                II     104   c                                                                III    366   e                                                                IV     475                                         2,6-dibromo-3,4,5-trihydroxy                                                                      10            490   d                                                                I      251   e                                                                II     347   g                                     2,4-dihydroxy-3,5-diiodo                                                                          10     II     255   y                                                                III    179   t                                     2,3,4,5-tetrabromo-6-hydroxy                                                                      10     III    186   g                                     2,3,5,6-tetrabromo-4-hydroxy                                                                      10     IV     47    b                                     2,3,4,6-tetrachloro-5-hydroxy                                                                     10            144   e                                     2,3,6-tribromo-4,5-dihydroxy                                                                      10            401   d                                                                I      193   b                                     2,4,6-tribromo-3,5-dihydroxy                                                                      10            406   j                                     2,4,6-tribromo-3-hydroxy                                                                          10            145   h                                                                II     84    d                                     ______________________________________                                    

The halogenated carboxylic acids 56 which serve as the precursors forthe halogenated acid chlorides 52 and halogenated alcohols 62, which inturn provide the alkyl portion of the ester of the invention as shown inequations 1 and 2, are prepared in any of the several ways known to theart. For example, perfluoro carboxylic acids containing up to 8 carbonatoms are commercially available from 3M by electrochemical fluorinationof the corresponding alkyl carboxylic acids. They can also be preparedby a telomerization reaction involving trifluoriodomethane andtetrafluoroethylene as shown in Equation 4. ##STR19##

Halogenated alkyl carboxylic acids 56 containing mixed halogens areprepared in various ways, the most widely applicable beingtelomerization of substituted halogenated ethylenes 72 with halogencontaining materials 74 and/or addition of 74 across the double bond of72. to yield a mixture 76 of adduct and telomers, y being 1 for theadduct and greater than 1 for telomers, followed by separation andhydrolysis to yield the final halogenated carboxylic acids 78 as shownin equation 5 below. ##STR20##

The halogen-containing material 74 employed in the reaction shown inequation 5 is generally an alkyl halide, but may also be a mixed halogensuch as ICl, or IBr, or a material capable of providing chlorine atoms,such as sulfuryl chloride, SO₂ Cl₂. Table v below provides a list ofrepresentative halogenated ethylenes useful in the reaction shown inequation 5 for the preparation of halogenated alkyl carboxylic acids 56.

                  TABLE V                                                         ______________________________________                                        Representative Halogenated Ethylenes                                          Useful for Preparation of R'--CO.sub.2 H                                      ______________________________________                                        CFCl═CFCl       CHCl═CHCl                                             CF.sub.2 ═CFCl  CF.sub.2 ═CH.sub.2                                    CF.sub.2 ═CCl.sub.2                                                                           CF.sub.2 ═CHCl                                        CF.sub.2 ═CF.sub.2                                                                            CF.sub.2 ═CHF                                         CCl.sub.2 ═CCl.sub.2                                                                          CHCl═CCl.sub.2                                        CFBr═CF.sub.2   CHBr═CF.sub.2                                         CFBr═CFBr       CH.sub.2 ═CClF                                        CF.sub.2 ═CFBr                                                            CF.sub.3 --CCl═CCl.sub.2                                                                      CF.sub.3 --CBr═CH.sub.2                               CF.sub.3 --CCl═CF.sub.2                                                                       CF.sub.3 CH═CF.sub.2                                  CF.sub.3 --CF═CF.sub.2                                                                        CF.sub.3 CH═CF.sub.2                                  (CF.sub.3).sub.2 C═CF.sub.2                                                                   CF.sub.2 Br--CH═CF.sub.2                              CF.sub.2 Br--CBr═CF.sub.2                                                                     CF.sub.2 Br--CF═CF.sub.2                              CF.sub.3 --CBr═CFBr                                                                           CCl.sub.3 --CF═CHCl                                   CF.sub.2 Cl--CF═CF.sub.2                                                  CF.sub.3 --CF═CF--CF.sub.3                                                CF.sub.3 --CCl═CCl--CF.sub.3                                              C.sub.2 F.sub.5 --CF═CF.sub.2                                             CF.sub.3 CH═CFCH.sub.3                                                    ______________________________________                                    

Table VI below provides a listing of representative halogenated alkyls74 useful for the preparation of halogenated alkyl carboxylic acids 56via the reaction shown in equation 5.

                  TABLE VI                                                        ______________________________________                                        Representative Halogenated Alkyls                                             Useful for Preparation of R'--CO.sub.2 H                                      ______________________________________                                        CCl.sub.3 --Br     (CF.sub.3).sub.2 CF--I                                     CCl.sub.3 --I      CF.sub.2 Br--CFClBr                                        CF.sub.3 --I       CF.sub.2 Cl--CFCl--I                                       CF.sub.2 Br.sub.2  CF.sub.3 CClBr.sub.2                                       CF.sub.2 ClBr      CF.sub.3 CBr.sub.3                                         C.sub.2 F.sub.5 I  CF.sub.3 CCl.sub.3                                         CF.sub.2 I--CF.sub.2 I                                                                           CF.sub.2 Br--CF.sub.2 I                                    C.sub.3 F.sub.7 I                                                             ______________________________________                                    

In general, any of the olefins shown in Table V (and also many othersknown to those skilled in the art and shown in the literature) may beemployed in the reaction of equation 5, to react with any of thematerials listed in Table VI (as well as many other halogenated alkylsknown to the art and shown in the chemical literature), so long as theratio of hydrogen atoms to carbon atoms in the resulting product doesnot exceed 1. The compounds 76 are produced as a mixture of materials,the complexity of which is determined by the particular chemicals beingreacted, and by the severity of the reaction conditions. In theadduct/telomer mixture 76, y is generally between 1 and 10 and thedirection of olefin addition is generally orderly, though in some caseshalogens on the olefinic component 72 may be shifted. The mixture 76 ispurified by chromatography or careful distillation, to yield theseparate adducts and telomers in a reasonably pure form. A desired pureadduct or telomer is then selected and hydrolyzed to yield thehalogenated carboxylic acid 78. The hydrolysis reaction may causeoxidation of both ends of the material undergoing reaction, depending onits chemical constitution. In practice, a mixture of carboxylic acids isgenerally produced in the hydrolysis reaction, and these are convertedto their methyl esters, which are in turn purified by chromatography ordistillation and then hydrolyzed back to the desired carboxylic acid.The hydrolysis step generally employs either fuming sulfuric acid orconcentrated (98%) sulfuric acid, and employs selected times andtemperatures, depending on the particular material being hydrolyzed.

Some examples of the preparation of halogenated alkyl carboxylic acids56 by the reaction shown in equation 5 are given below.

In Example 1, trifluorobromoethylene 80 is shown reacting with sulfurylchloride in the presence of a free radical initiator such asazobisisobutyronitrile to yield a mixture of adducts and telomericspecies represented by formulae 82 and 84. The bromine at the chain endin material 84 is derived from the starting material 80. This mixture iscarefully fractionally distilled, several times if necessary, to yieldultimately several fractions of separated materials, each having highpurity. One or more of these is selected for further work. In theexample, a chlorine-terminated telomer 86 containing 2 monomer units isshown as having been selected for further reaction. Material 86 is firsthydrolyzed with fuming sulfuric acid, then treated with methanol andfinally the reaction mixture is purified by distillation to yield themethyl ester 88, which is either hydrolyzed to the correspondingcarboxylic acid 90 or converted directly by means of thionyl chlorideand pyridine to the final acid chloride product 92.

EXAMPLE 1 ##STR21##

In an alternative procedure, shown in example 2, the same startingmaterials yield the same initial mixture of adducts and telomers as inexample 1, but now the subsequent fractional distillation providesproduct fractions each having the same carbon number but containingseveral different materials. In the example these are shown as 94 and96. The selected product mixture is subjected to sulfuric acidhydrolysis followed by esterification with methanol to yield a mixtureof the corresponding methyl esters 98 and 100. This mixture of esters isdehalogenated with zinc and methanol to yield the olefinic ester 102,which is in turn brominated to yield ester 104. Compound 104 can behydrolyzed to the corresponding carboxylic acid and then converted tothe acid chloride 106, or may be converted directly to the acid chlorideas shown in the example.

EXAMPLE 2 ##STR22##

In example 3 trifluorochloroethylene 108 is shown reacting with sulfurylchloride and a free radical initiator such as azobisisobutyrlnitrile toyield a mixture 110 of adducts and telomers, which is then fractionallydistilled to yield a selected telomer 112 which contains 4 monomerunits. This is subjected to hydrolysis by fuming sulfuric acid and theresulting acid mixture is esterified to yield a mixture of esters 114and 116. These materials are separated by distillation, yielding pureester 116. This material may be hydrolyzed to the correspondingcarboxylic acid which can then be converted to the acid chloride 118, orester 116 can be directly converted to the acid chloride by treatmentwith thionyl chloride and pyridine, as shown in the example.

EXAMPLE 3 ##STR23##

In example 4, trifluorobromoethylene 80 is shown reacting withbromotrichloromethane in the presence of a free radical initiator toyield a mixture 120 of adducts and telomers. This product mixture iscarefully fractionally distilled and a desired telomer is selected, thisselected telomer being shown as compound 122 in the example. Upontreatment of compound 122 with fuming sulfuric acid, followed byesterification with methanol, a mixture of esters 124 and 126 isproduced. These materials are separated by distillation, yielding pureester 124. Compound 124 may be hydrolyzed to the correspondingcarboxylic acid, which can then be converted to acid chloride 126, orcompound 124 can be converted directly to acid chloride 126 by treatmentwith thionyl chloride and pyridine as shown in the example. Startingwith trifluorochlorethylene instead of trifluorobromoethylene wouldproduce similar products, but with chlorine in the chain instead ofbromine.

EXAMPLE 4 ##STR24##

Example 5 shows the reaction of trifluorobromoethylene 80 withtrifluoroiodomethane in the presence of a free radical initiator toyield a mixture 128 of adducts and telomers, which is in turn carefullydistilled to yield the desired adduct 130. Compound 130 adds across thedouble bond of tetrachloroethylene 132 to yield adduct 134, which ishydrolyzed and then esterified to yield the ester 136. Ester 136 can behydrolyzed to the corresponding carboxylic acid, which can in turn beconverted to acid chloride 138, or it may be converted directly intoacid chloride 138 by treatment with thionyl chloride and pyridine.

EXAMPLE 5 ##STR25##

In example 6 dichlorodifluoroethylene 140 is shown reacting in thepresence of a free radical initiator with the halogenated alkane 142 toyield a mixture 144 of adducts and telomers. This is distilled and thedesired adduct 146 is selected and then reacted further with halogenatedolefin 148 to yield compound 150. Upon mild oxidation compound 150 isconverted to halogenated ketone 152, which upon reaction with sulfurtetrafluoride yields the halogenated alkane 154. This is hydrolyzed withfuming sulfuric acid and the resulting mixture is esterified withmethanol to produce ester 156. Compound 156 may be hydrolyzed to thecorresponding carboxylic acid which then can be converted to the acidchloride 158 by treatment with thionyl chloride, or compound 156 may beconverted directly to the acid chloride 158 by treatment with thionylchloride and pyridine.

EXAMPLE 6 ##STR26##

In example 7 halogenated olefin 148 is shown reacting with alkyl halide142 to yield, after suitable workup, the compound 158. This is thenadded across the double bond of dichlorodifluoroethylene 140 to yieldcompound 160 after workup. This is hydrolyzed with sulfuric acid andesterified to yield a mixture of esters from which compound 162 isisolated by appropriate purification procedures. As before, the estercan be hydrolyzed to the corresponding carboxylic acid, which then canbe converted to the acid chloride, or compound 162 can be converteddirectly to the acid chloride by reaction with thionyl chloride andpyridine.

EXAMPLE 7 ##STR27##

In example 8 the dibromodifluoroethylene 162 is shown reacting withtrifluoroiodomethane in the presence of a free radical initiator toyield a mixture 164 of adducts and telomers, from which a particulartelomer 166 is obtained by distillation and selection of the appropriatefraction. Compound 166 is hydrolyzed with sulfuric acid and subsequentlyesterified with methanol to yield ester 168, which can be hydrolyzed tothe corresponding carboxylic acid, and this in turn can be readilyconverted to the acid chloride by treatment with thionyl chloride.Alternatively, compound 168 can be converted to the acid chloridedirectly by treatment with thionyl chloride and pyridine.

EXAMPLE 8 ##STR28##

In example 9 the known dibromohydroxybenzoic acid 170 is shown reactingwith an alcohol to yield ester 172, which upon treatment with a weakbase such as potassium carbonate and then an acid chloride yieldsdiester 174. It will be appreciated that R in the alcohol and R' in theacid chloride need not be the same. Preparation of halogenated alcoholsand acid chlorides has been discussed above.

EXAMPLE 9 ##STR29##

As indicated above, the fluids of the invention find their primaryutility as flotation and damping fluids in floated inertial instrumentssuch as certain gyroscopes and accelerometers. Such instruments areillustrated in the figures and discussed below. The fluids referred toare preferably the compounds of the present invention.

Both a gyroscope (gyro) and an integrating pendulous accelerometer areillustrated generically in FIG. 1, which shows a float 10 which isbuoyantly supported by a viscous damping fluid 12 within an outerhousing 14. Within float 10 is an inertial sensing element 16, which inthe case of a gyro is a spinning wheel and in the case of an integratingpendulous accelerometer is a pendulum. At one end of float 10 and outerhousing 14 respectively are electromagnetic sensing elements 18 and 18'.At the other end of float 10 and outer housing 14 respectively areelectromagnetic torquing elements 20 and 20'. Orthogonal axes 22, 24,and 26 are the input axis, output axis, and spin or pendulous axis,respectively. Forces acting on the devices at input axis 22, i.e.,rotation about axis 22 in the case of a gyro and acceleration along axis22 in the case of an integrating pendulous accelerometer, tend to movefloat 10 relative to output axis 24, and produce a signal at the sensingelements 18 and 18'. Float motion is offset by a corresponding torquerebalance signal applied to the torquing elements 20 and 20'.

A related instrument is a pendulous integrating gyroscopic accelerometer(PIGA), shown generically in FIG. 1A. In this instrument a pendulousintegrating gyroscope (PIG) of FIG. 1 wherein inertial sensing element16 includes both a spinning wheel and a pendulum is supported on abearing 28 and spindle 30, which assembly provides 360 degrees ofrotational freedom about the input axis 22. The support bearing 28 ismounted on a stationary housing 32. The angular rate of the PIG aboutaxis 22 is applied by a torque motor 34 which is controlled through thesignal produced by the sensing elements 18 and 18'. Power from thestationary housing 32 to the rotating PIG is supplied through a slipring 35. The PIG is shielded from the external environment by an outerhousing 36, and is buoyantly supported by a fluid inside housing 36.This reduces accelerator input axis position sensitivity to cross-axisaccelerations. This fluid also lubricates slip ring 35 and input axisbearing 28.

EXPERIMENTAL 2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride

To an evacuated 3 liter high pressure reactor containing 10.6 g ofazobisisobutyronitrile was added 540 g (4 moles) of SO₂ Cl₂ and 1,288 g(8 moles) of bromotrifluoroethylene. The reactor was heated, withrocking, to 90° C. and maintained at this temperature for 4 hours. Themaximum pressure noted was 400 psig. The volatiles were vented, leavinga mixture of higher boiling telomers. Several similar preparations wereconducted to yield a large volume of crude telomer for furtherpurification and conversion to final products. The crude telomer wasdistilled several times to a final purity of greater than 90% by theprocedure described below.

8 liters of crude telomer was placed in a 12 liter round bottom flaskattached to a distillation still, the pressure was reduced to about 15mm of Hg, and the material was distilled quickly to remove low and highboilers. Fractions boiling between 142° C. and 146° C. were collected.These amounted to 5 liters and constituted a mixture containing about75% of Cl--(CF₂ --CFBr)₂ --Cl plus some Br--(CF₂ --CFBr)₂ --Cl and smallamounts of other materials.

The collected fractions were distilled using a spinning band still witha reflux ratio of 15:1 and a band spinning rate of 2,500 rpm. Fractionsboiling between 145° C. and 176° C. were collected and pooled, yielding3 liters of the telomer mixture, containing about 88% Cl(CF₂ --CFBr)₂--Cl. Redistillation under the same conditions yielded 2.5 liters ofmaterial having a purity shown to be about 92% by gc and lc.

The purified telomer mixture (500 g) wa refluxed with 500 ml of 33%oleum (fuming sulfuric acid) with constant stirring for 24-26 hrs, thenallowed to cool. When the mixture had cooled, 1,000 ml of methanol wasadded dropwise at a rate sufficient to maintain a gentle reflux. Afterthe methanol addition, the mixture was stirred until cool then allowedto separate, and the lower (organic) layer was withdrawn. The upperlayer was shaken with water, allowed to separate, and again the lowerorganic layer was withdrawn. The two fractions of methyl ester werecombined, yielding approximately 500 g of a mixture of methyl esters.This mixture was distilled in a spinning band distillation apparatususing a reflux ratio of 30:1 and a spin rate of 2,500 rpm. Fractionsboiling between 157° C. and 162° C. were collected, yielding 420 g ofdistilled material. The product was redistilled under the sameconditions, yielding 375 g of the methyl esters Cl--CF₂ --CFBr--CF₂--CO₂ CH₃ and Br--CF₂ --CFBr--CF₂ --CO₂ CH₃. This material was analyzedby gc and shown to be greater than 95% pure chlorine initiated material.

The mixture of purified methyl esters was dissolved in 300 ml ofmethanol and added dropwise with stirring to a mixture of 159 g of zincdust and 500 ml of methanol over a period of 4 hrs, maintaining a gentlereflux without supplemental application of heat. After the addition wascomplete, heat was applied and the mixture was refluxed a further 1.5-2hrs. The reaction was not allowed to proceed longer than this becauseprolonged reflux causes the generation of objectionable byproducts inthe reaction. The reaction mixture was cooled to room temperature,unreacted zinc was removed by filtration through celite, and theresulting unsaturated product, CF₂ ═CF--CF₂ --CO₂ CH₃, was washedseveral times with water, finally yielding 180 g of material. Thisproduct was distilled on the spinning band distillation apparatus at areflux ratio of 30:1 and a spin rate of 2,500 rpm, fractions boilingbetween 95° C. and 96° C. being collected. The yield after distillationwas 117 g. This was redistilled three times under the same conditionsuntil gc/ms analysis showed product of approximately 98% purity. Theyield in this step was 100 g of unsaturated ester.

Bromine liquid (89 g) was added dropwise and with stirring to 100 g ofthe unsaturated ester over a period of 3-4 hrs. After an inductionperiod during which about 10% of the bromine was added, the solutionbecame decolorized and began to boil. Bromine addition was continued ata rate sufficient to maintain gentle refluxing. After about 70% of thebromine had been added the mixture darkened and began to cool. After thebromine addition was complete, the solution was allowed to cool, theproduct mixture (about 200 ml) was washed with aqueous sodium bisulfitesolution, and the organic layer was separated. The yield was 155 g ofcrude BrCF₂ --CFBr--CF₂ --CO₂ CH₃. This product was distilled on thespinning band distillation apparatus at a reflux ratio of 30:1 and aspin rate of 2,500 rpm. Fractions boiling between 171° C. and 175° C.were collected. The product was redistilled under the same conditions toyield 110 g of purified material, shown by gc/ms to be greater than 95%pure. This was stored in a sealed container wrapped in foil.

To 160 g of stirred BrCF₂ --CFBr--CF₂ --CO₂ CH₃ in a flask was added 20g of pyridine. Thionyl chloride (85 g, an excess) was added dropwiseover 1.5-2 hrs at a rate sufficient to cause and maintain a gentlereflux. After the addition of thionyl chloride was complete, the mixturewas refluxed a further 16 hrs, then cooled to room temperature, allowedto separate, and the acid chloride (lower) layer was removed. This wasdistilled on the spinning band apparatus under the same conditions aspreviously employed, using a cold trap on the vents of the apparatus tokeep the distillation dry and to trap thionyl chloride and acid vapors.Fractions boiling between 135° C. and 136° C. were collected andcombined. The product was redistilled several times to ultimately yield97 g of BrCF₂ --CFBr--CF₂ --COCl which was shown by gc/ms to be 99%pure.

(2,4,6-tribromophenyl)-2,2,3,4,4-pentafluoro-3,4-dibromo-butyrate

153 grams of tribromophenol and 36.5 grams of pyridine were dissolved in350 ml of methylene chloride. 164 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel with stirring 2.2 grams ofdimethylaminopyridine were then added and the solution was stirred.After 0.5 hour, an additional 500 ml of methylene chloride were addedand the mixture stirred for an additional 3.5 hours. The mixture waswashed in a separatory funnel three times with 500 ml of DI water, thenfiltered through a column of silica and the solvent evaporated. Thematerial was then chromatographed on a column of silica using FREON 113(trichlorotrifluorethane) as eluent. The sample (220 grams) was shown tobe pure ester by gc/ms. m/e 62 (27%, C₅ H₂); 69 (21%, CF₃); 129 (33%,CF₂ Br); 131 (100%, CF₂ Br and C₃ F₅); 141 (26%, C₅ H.sub. 2 Br); 143(26%, C₅ H₂ Br); 327, 329, 331, 333 (10%, 27%, 24%, 9% all C₆ Br₃ H₂ O).I.R.(ν, in cm⁻¹)=3110, 3070 (Ar--H); 1800 (C═O); 1550, 1430 (Ar C═C).

(2,4,6-tribromoresorcinyl)-bis-2,2,3,4,4-pentafluoro-3,4-dibromobutyrate

27.9 grams of tribromoresorcinol and 12.7 grams of pyridine weredissolved in 200 ml of methylene chloride. 57.1 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel with stirring. 0.38 grams ofdimethylaminopyridine were added and the solution stirred. After 1.5hours, an additional 100 ml of methylene chloride were added and themixture stirred for an additional 3 hours. The mixture was washed in aseparatory funnel twice with 500 ml of DI water, then filtered through acolumn of silica and the solvent evaporated. The material was thenchromatographed on a column of silica using FREON 113(trichlorotrifluorethane) as eluent. The sample (59 grams) was shown tobe pure ester by gc/ms. m/e 69 (19%, CF₃); 129 (33%, CF₂ Br); 131 (100%,CF₂ Br and C₃ F₅); 289, 291, 293 (7%, 12%, 6% all CF₂ BrCFBrCF₂). I.R.(ν, in cm⁻¹)=3120, 3080 (Ar--H); 1805 (C═O); 1560, 1440 (Ar C═C).]

(2,4,6-trichloro-3-ethyl-phenyl)-2,2,3,4,4-pentafluoro-3,4-dibromobutyrate

46.7 grams of trichloroethylphenol and 16.3 grams of pyridine weredissolved in 300 ml of methylene chloride. 73.3 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel with stirring. 1.0 gram ofdimethylaminopyridine was added and the solution stirred. After 1 hour,an additional 200 ml of methylene chloride were added and the mixturestirred for an additional 3 hours. The mixture was washed in aseparatory funnel twice with 500 ml of DI water, then filtered through acolumn of silica and the solvent evaporated. The material was thenchromatographed on a column of silica using FREON 113(trichlorotrifluorethane) as eluent. The sample (100.7 grams) was shownto be Pure ester gc/ms. m/e (chemical ionization) 69 (22%, CF₃); 109,111, 113 (9%, 3%, 0.5%, all C₃ H₃ CL₂); 123, 124, 125, 127 (12%, 4%,18%, 5%, unassigned); 129 (35 %, CF₂ Br); 131 (100%, CF₂ Br and C₃ F₅);159, 160, 161, 162, 163, 165 (21%, 21%, 13%, 16%, 2%, unassigned); 223,225, 227, 229 (70%, 65%, 20%, 2% (all C₈ H₆ Cl₃ O); 289, 291, 293 (4%,9%, 4% all C₃ F₅ Br₂); 540, 542, 544, 546, 548, 550 (2%, 5%, 7%, 3%,0.6%, 0.1%, molecular ion). I.R.(ν, in cm⁻¹)=3080 (Ar--H); 2970, 2930,2870 (R--H); 1805 (C═O); 1570, 1450 (Ar C═C).

(2,4,6-triiodophenyl)-2,2,3,4,4-pentafluoro-3,4-dibromo-butyrate

100 grams of triiodophenol were dissolved in 100 ml of pyridine withwarming to 50° C. 75 grams of 2,2,3,4,4-pentafluoro-3,4-dibromo-butyrylchloride were added dropwise through a dropping funnel with stirring atsuch a rate that the temperature did not rise above 65° C. The mixturewas stirred at 50° C. for an additional 30 minutes, then overnight atroom temperature. The mixture was washed in a separatory funnel threetimes with 500 ml of DI water, then filtered through a column of silicaand the solvent evaporated. The material was then chromatographed on acolumn of silica using FREON 113 (trichlorotrifluroethane) as eluent.Chromatography on silica gave 75.5 grams of material 99% pure. Thematerial solidified at room temperature and has a melting point of 50°C. I.R.(ν, in cm⁻¹)=3050, 3090 (Ar--H); 1800 (C═O); 1570, 1415 (Ar C═C).m/e 62 (47%, C₅ H₂); 69 (18%, CF₃); 129 (22%, CF₂ Br); 131 (70%, CF₂ Brand C₃ F₅); 189 (60%, C₅ H₂ I); 344 (56%, C₆ H₂ I₂ O); 471 (100%, C₆ H₂I₃ O).

Synthesis of Meta Substituted Triiodophenols

Though a large number of halogenated phenols have been reported in theliterature, one skilled in the art is not limited to such reportedhalogenated phenolic compounds. For example, a procedure reported forthe synthesis of triiodophenol (P. Chabrier, J. Seyden-Penne, and A. M.Fouace, Compt. Rend., 245, 174 (1957)) was used with meta bromophenol,meta ethylphenol and meta methylphenol to form the corresponding metasubstituted triiodo compounds, which were then converted to the desiredesters. The above paper is hereby incorporated by reference.

(2,4,6-triiodo-3-bromo-phenyl)-2,2,3,4,4-pentafluoro-3,4-dibromobutyrate

20.3 grams of 3-bromo-2,4,6-triiodophenol (m.p 155°-157° C.) weredissolved in 50 ml of pyridine 13.0 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel with stirring. The mixture was stirredovernight at room temperature. The mixture was washed in a separatoryfunnel twice with 250 ml of DI water, then filtered through a column ofsilica and the solvent evaporated. The material was then chromatographedon a column of silica using FREON 113 (trichlorotrifluroethane) aseluent. The sample (25 grams), which slowly crystallized at roomtemperature, was shown to be pure ester (97%) by gc/ms. It is suitablefor use as a fluid above its melting point of 56°-57° C. m/e (chemicalionization) 129 (21%, CF₂ Br); 131 (100%, CF₂ Br and C₃ F₅); 140 (13%,C₅ HBr); 142 (13%, C₅ HBr); 188 (14%, C₅ HI); 267, 269 (11%, 10% C₅BrIH); 315 (4%, C₅ I₂ H); 422, 424 (6%, 7%, C₆ I₂ HBrO); 549, 551 (5%,4%, C₆ I₃ HBrO); 866, 868, 870, 872 (0.2%, 0.6%, 0.4%, 0.2%, molecularion). I.R.(ν, in cm⁻¹) =3080 (Ar--H); 1800 (C═O); 1550, 1520 (Ar C═C).

(3-methyl-2,4,6-triiodophenyl)-2,2,3,4,4-pentafluoro-3,4-dibromobutyrate

10 grams of 3-methyl-2,4,6-triiodophenol and 1.6 grams of pyridine weredissolved in 300 ml of methylene chloride. 7.3 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel to the stirring phenol/pyridine solution. 0.2gram of dimethylaminopyridine was added. The mixture was stirred for anadditional 4 hours, then was washed twice with 500 ml DI water in a1,000 ml separatory funnel, filtered through a column of silica, and thesolvent evaporated. The material was then chromatographed on a column ofbasic aluminum oxide using FREON 113 (trichlorotrifluroethane) aseluent. A final yield of 11 grams of ester was obtained. The materialwas shown by gc/ms to be pure ester I.R (ν, in cm⁻¹) =3100, 3070(Ar--H); 2950, 2920 (Me C-H); 1800 (C═O); 1545, 1520 (Ar C═C). m/e 76(61%, C₆ H₄); 129 (40%, CF₂ Br); 131 (100 %, CF₂ Br and C₃ F₅); 203(61%, C₅ HICH₃); 231 (28%, C₆ HICH₃ O); 358, (42%, C₆ HI₂ CH₃ O); 485,(66%, C₆ I₃ HCH₃ O).

(3-ethyl-2,4,6-triiodophenyl}-2,2,3,4,4-pentafluoro-3,4-dibromobutyrate

20 grams of 3-ethyl-2,4,6-triiodophenol and 3.15 grams of pyridine weredissolved in 300 ml of methylene chloride. 14.1 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel to the stirring phenol/pyridine solution. 0.2gram of dimethylaminopyridine was added. The mixture was stirred for anadditional 4 hours, then was washed three times with 500 ml DI water ina 1,000 ml separatory funnel, filtered through a column of silica, andthe solvent evaporated. The material was then twice chromatographed oncolumns of silica using FREON 113 (trichlorotrifluroethane) as eluent. Afinal yield of 29 grams of ester was obtained. The material was shown bygc/ms to be pure ester. I.R.(ν, in cm⁻¹) =3090, 3070 (Ar--H); 2970,2930, 2870 (Me C--H); 1800 (C═O); 1545, 1530 (Ar C═C). m/e 69 (31%,CF₃); 89 (70%, C₇ H₅); 129 (42 %, CF₂ Br); 131 (100%, CF₂ Br and C₃ F₅);357 (34%, C₇ H₃ I₂ O); 372 (34%, C₂ H₅ C₆ HI₂ O); 499 (49%, C₂ H₅ C₆ HI₃O).

(2,3,4,6-tetrabromophenyl)-2,2,3,4,4-pentafluoro-3,4-dibromobutyrate

150 grams of 2.3.4.6-tetrabromophenol and 3.15 grams of pyridine weredissolved in 500 ml of methylene chloride. 140 grams of2,2,3,4,4-pentafluoro-3,4-dibromo-butyryl chloride were added dropwisethrough a dropping funnel to the stirring phenol/pyridine solution. 2.4grams of dimethylaminopyridine were added. The mixture was stirredovernight (16 hours), then was washed three times with 500 ml DI waterin a 1,000 ml separatory funnel, filtered through a column of silica,and the solvent evaporated. The material was then chromatographed threetimes on columns of basic aluminum oxide using FREON 113(trichlorotrifluroethane) as eluent. A final yield of 230 grams of esterwas obtained. The material was shown by gc/ms to be pure ester (99%).I.R.(ν, in cm⁻¹)=3100, 3060 (Ar--H); 1805 (C═O); 1545, 1535 (Ar C═C).m/e 61 (14%, C₅ H); 69 (15%, CF₃); 129 (26%, CF₂ Br); 131 (100%, CF₂ Brand C₃ F₅); 140 (13%, C₅ HBr); 142 (13%, C₅ HBr); 219, 221, 223 (9%,17%, 8%, all C₅ Br₂ H); 405, 407, 409, 411, 413 (2%, 11%, 14%, 7%, 2%,all C₆ Br₄ HO).

Methyl-3,5,7,8-tetrachloro-2,2,3,4,4,5,6,6,7,8,8-undecafluoro octanoate

A 5 gal Hastelloy C stirred autoclave fitted with a dip tube and valve,overgas valve, thermowell, 1,000 psig teflon-coated Inconel rupture discwas set up in a safety containment tank having a 200 psi rupture disc.Reagent grade concentrated sulfuric acid (2,800 ml) was measured into adry flask, and 1,400 ml of fuming sulfuric acid (27-33% SO₃) were addedcarefully with stirring, care being taken to minimize exposure toatmospheric moisture. The autoclave was evacuated to a pressure ofapproximately 28 inches of mercury by means of an aspirator, then sealedoff to maintain the vacuum. 5 kg of 98% pure CTFE tetramer, Cl(CF₂--CFCl)₄ --Cl, were weighed into a suitable container, connected to theautoclave via tubing, then drawn into the autoclave reactor through theliquid sampling valve and dip tube, by the residual vacuum. Theautoclave stirrer was adjusted to 500 rpm. Next, the sulfuric acidsolution was similarly drawn into the reactor. Pressure and temperaturesensors were set to sound alarms at 500 psig and 240° C. respectively.The temperature of the reaction was raised in 50° C. increments every0.5 to 0.75 hrs until a temperature of 215° C. was reached. Thistemperature was then maintained for the remainder of the predetermined17 hr run time. At the conclusion of the run, the reaction mixture wascooled to 60° C. and sampled to test for completeness of reaction.

A 10 ml representative sample was removed, carefully added to an excessof methanol, and stirred for 10 minutes while being heated. Aftercooling the mixture, water was added, the mixture was allowed toseparate, and the bottom layer was isolated and analyzed by gc. Testcriteria were as follows. If the amount of monoester was found to beless than 70% of the mixture, the amount of starting tetramer greaterthan 10%, and the amount of diester less than 15%, the reaction wascontinued for an additional 4 hrs. On the other hand, if the monoesterconstituted at least 70% of the mixture, the starting tetramerconstituted less than 10%, and the diester constituted 15% or greater,the reaction was considered complete.

At the completion of the reaction, heating was discontinued and thereaction mixture was cooled to approximately 50° C. The mixture was thenslowly discharged into a 22 liter three-neck flask, the transfer beingaccomplished by providing a suitable connecting tube between the diptube of the autoclave and a neck of the receiving flask, then evacuatingthe receiving flask slightly by means of an aspirator. The transferredreaction mixture was allowed to settle overnight, separating into twolayers.

The bottom layer of the hydrolyzed mixture was separated and addedrapidly to 6 liters of methanol in a 12 liters flask, then refluxedovernight. The resulting mixture was then allowed to separate and thecolorless ester bottom layer was drawn off. The top layer was extractedtwice with FREON 113 and added to the ester lower layer. The resultingmixture of ester and FREON 113 was neutralized with sodium bicarbonate,washed with D.I. water, and distilled. Distillation at a headtemperature of 72° C. and 0.16 ml of mercury produced the desired methylester in 99+% purity.

(2,4,6-tribromophenyl)-2,2,3,4,4-pentafluoro-3-bromo-4-chlorobutyrate

This was prepared like the corresponding dibromo material, but using2,2,3,4,4-pentafluoro-3-bromo-4-chlorobutyryl chloride purchased fromPCR. I.R.=1,800 cm⁻¹. m/e 69(49%,CF₃); 85, 87 (45%, 17%, CF₂ Cl); 129(31%, CF₂ Br); 131 (99%, CF₂ Br, C₃ F₅); 141,143 (48%, 47%, C₅ H₂ Br);299, 301, 303, 305 (18%, 44%, 42%, 14%, C₅ Br₃ H₂); 327, 329, 331, 333(39%, 100%, 96%, 34%, C₆ Br₃ H₂ O); 602,604,605,606,608,610 (17%, 28%,24%, 9%, 1%, C₁₀ H₂ Br₄ ClF₅ O₂).

Pin-on-Disc Wear Test for Measurement of Qualitative Wear AssociatedWith Use of the Compounds of the Invention as Lubricants

In pin-on-disc testing a weighted pin (preferably having a radius at thetip) was placed in contact with a rotating metallic disc, and the weartrack on the disc as well as the torque required to restrain the pinwere measured. The equation relating the torque to the frictioncoefficient is

    T=μPR

where μ is the friction coefficient, P is the load on the pin, and R isthe wear track radius. The disc was typically of brass, the surface ofwhich was plated successively with nickel and with about 10 microns ofgold. The weight on the pin was typically 250 g. The pin itself wastypically an alloy of gold, specifically, Neyoro G. Tests of severalexperimental fluids and appropriate controls were run on each test disc,krytox being used as the standard.

The wear tester is an apparatus for keeping two contacting specimens inrelative motion under a known load. It has a means for measuring therestraining force or the torque developed, thus permitting thecoefficient of friction to be determined, as indicated above.

Measurement of the frictional torque (and hence the coefficient offriction) developed between the two specimens was accomplished with aBendix double reed flex-pivot coupled to a microsyn signal generatorrotor and provided with variable damping. The flex-pivot is basically alinearly elastic torsional spring, the angular deflection of which isproportional to an applied torque. In the test procedure, the stationaryspecimen is mounted on the flex-pivot. When the disc upon which the pinis riding rotates, a torque is applied to the pin and hence to the armof the flex-pivot. Since the signal generator rotor moves from the nullposition when torque is applied, a voltage signal is generated theamplitude of which is proportional to the magnitude of the appliedtorque.

The width and depth of the wear track in the disc were measured by aSloan Dektak II Profilometer at several points along the wear track, andaveraged.

Test results on a given plate can be compared, but it is more difficultto compare tests run on different plates, since no two plates areexactly identical.

The above-described wear tester and its method of use are more fullydescribed in Report No. C-5413 by K. E. Koehler of The Charles StarkDraper Laboratory, Inc., 1981, which report is hereby incorporated byreference.

In Table VII below are shown the results of qualitative pin-on-disc weartests of several of the exemplary compounds of the invention, relativeto Krytox. It will be noted that the compounds of the inventionperformed better than Krytox in reducing wear.

                  TABLE VII                                                       ______________________________________                                        Wear Data (Pin-on-Disc)*                                                      Material Wear Track    Wear Track Wear                                        Tested.sup.a                                                                           Width.sup.b   Depth.sup.b                                                                              Area.sup.b                                  ______________________________________                                        Krytox   1.00          1.00       1.00                                        1        1.00          0.50       0.50                                        2        1.00          0.50       0.50                                        7        1.00          0.50       0.50                                        ______________________________________                                         *Tests were run at 1 rpm under a 250 g load for 24 hours at 1 RPM.            .sup.a numbers shown in the first column refer to synthesized exemplary       compounds of TABLE I                                                          .sup.b relative to Krytox                                                

Although the fluids of the invention and their methods of preparationhave been exemplified by specific compounds and reactions, those skilledin the art will recognize that certain other compounds and reactionconditions are within the intended scope of the invention. Accordingly,the invention is to be limited only by the scope of the appended claims.

What is claimed is:
 1. A method for lubricating a floated inertialinstrument, comprising the steps of:providing an inertial instrumenthaving a housing for containing an inertial sensing element and at leastone axis bearing; and introducing into said housing, said sensingelement, and said bearing, a lubricating compound having the generalformula ##STR30## wherein: X is a halogen selected from the groupconsisting of F, Cl, Br, and I, and n=1-5, the sum of the masses of saidhalogens being at least 90; Y is a substituent selected from the groupconsisting of --R, --OR, --CO₂ R, and --NO₂, wherein R is a straight,branched, or cyclic alkyl or haloalkyl group containing 1-4 carbonatoms, and m=0-2; Z is ##STR31## R' is a straight, branched, or cyclichaloalkyl group containing 2-8 carbon atoms and at least one F atom, theremaining halogen atoms of said R' group being selected from the groupconsisting of F, Cl, and Br, the halogens of said R' group replacingmore than 60% of the hydrogen atoms in a corresponding unhalogenated R'group, and wherein P=1-3.
 2. The method of claim 1 further comprisingthe step of providing an inertial instrument which further contains aslip ring, said slip ring being in electrical contact with said inertialsensing element.
 3. The method of claim 1 further comprising introducinga perfluoropolyether into said housing.
 4. The method of claim 1 whereinat least one substituent X is selected from the group consisting ofbromine and iodine.
 5. The method of claim 1 wherein at least onesubstituent Y is methyl or ethyl.
 6. The method of claim 1 wherein saidfloated inertial instrument is a gyroscope.
 7. The method of claim 1wherein said floated inertial instrument is an integrating gyroscopicaccelerometer.
 8. A method for lubricating a bearing supporting afloatable component, said method comprising the steps of:providing ahousing containing said bearing supporting said floatable component; andintroducing into said housing and said bearing, a lubricating compoundhaving the general formula ##STR32## wherein: X is a halogen selectedfrom the group consisting of F, Cl, Br, and I, and n=1-5, the sum of themasses of said halogens being at least 90; Y is a substituent selectedfrom the group consisting of --R, --OR, --CO₂ R, and --NO₂, wherein R isa straight, branched, or cyclic alkyl or haloalkyl group containing 1-4carbon atoms, and m=0-2; Z is ##STR33## R' is a straight, branched, orcyclic haloalkyl group containing 2-8 carbon atoms and at least one Fatom, the remaining halogen atoms of said R' group being selected fromthe group consisting of F, Cl, and Br, the halogens of said R' groupreplacing more than 60% of the hydrogen atoms in a correspondingunhalogenated R' group, and wherein p=1-3.
 9. A method for lubricating afloated inertial instrument, comprising the steps of:providing aninertial instrument having a housing for containing an inertial sensingelement and at least one axis bearing; and introducing into saidhousing, said sensing element, and said bearing, a lubricating compound,said compound consisting of a substituted or unsubstituted halogenatedaryl group linked by an ester to from one to three halogenated alkylgroups, said halogenated aryl group containing from 1-5 halogen atomsselected from the group consisting of F, Cl, Br, and I, the sum of themasses of said halogens being at least 90; said substituted halogenatedaryl group having, zero, one or two substituents selected from the groupconsisting of --R, --OR, --CO₂ R, and --NO₂, wherein R is a straight,branched, or cyclic alkyl or haloalkyl group containing 1-4 carbonatoms; said ester linkage being of the form ##STR34## and saidhalogenated alkyl group being a straight, branched, or cyclic haloalkylgroup containing 2-8 carbon atoms and at least one F atom, the remaininghalogen atoms of said halogenated alkyl group selected from the groupconsisting of F, Cl, and Br, the halogens of said haloalkyl groupreplacing more than 60% of the hydrogen atoms in a correspondingunhalogenated alkyl group.